6x11 - The Flying Doctors

A bloke and his girlfriend turn up in town to see David - they are old friends. David and the bloke go climbing, his girlfriend isn't feeling well and stays at the hotel. The girlfriend seems to be getting worse and when Nancy sees her she calls Tom. It turns out to be a very bad case of food poisoning. During the climb the bloke starts feeling ill and can't carry on, he waits on ledge half way up and David goes for help. The food poisoning was from some caviar and champagne they had both had.